docs: def _needs_dependencies(p_function):
      """
      A decorator that triggers the population of the dependency tree in a
      TodoList (and other administration). The decorator should be applied to
      methods of TodoList that require dependency information.
      """
      def build_dependency_information(p_todolist):
          for todo in p_todolist._todos:
              p_todolist._register_todo(todo)
  
      def inner(self, *args, **kwargs):
          if not self._initialized:
              self._initialized = True
  
              from topydo.lib.Graph import DirectedGraph
              self._depgraph = DirectedGraph()
  
              build_dependency_information(self)
  
          return p_function(self, *args, **kwargs)
  
      return inner